Foam Modelling

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Foam modelling

What is foam modelling and why do we need to make (a) foam model/s?

Foam modeling is a technique used to create three-dimensional prototypes or models using foam materials. It involves shaping, cutting, and assembling foam to build objects or structures that represent ideas or designs. Foam can be shaped using simple tools like knives, sandpaper, or hot wire cutters.

People make foam models as they are helpful for testing shapes, sizes, details, and knowing what improvements to make (on their next foam models) before creating the final product.

Base

For the base (and other parts) you will need double sided tape, a pair of scissors, pencil, paper, and your foam (block).

Start off by finding a foam block/ foam blocks depending on how big you want your base to be. For me I've stacked two of my foam blocks on top of each other to make it higher; as I figured that there won't be enough space to fit my design with uneven levels in one block without being able to show the difference of height in my design. The block is --- x --- (will add numbers later).

In my situation (stacking the blocks on top of each other), I used three rows of double sided tape to attach the two blocks together. I then used the scissors to cut out the remaining tape sticking out on the sides. Peeled off the paper and then stuck a foam block I got on the other carefully.

I'm going to draw my design from the side view so I flipped my block onto the side, then traced the sides of the block. this will be my template (I cannot draw my design bigger than the box or it won't fit).

As you can see I drew my design onto the paper already and you could also see the blocks. Now you'll need to cut out that box and then stick it onto your block with a double sided tape.

The cut out should fit perfectly onto the side of your foam block. After that bring it to the hot wire cutter and set it to around 11 - 13 depending on how big your block is.

When cutting with the hot wire always cut a bit further from the line you've drawn (your design) because most the time it may not be a perfect cut. Furthermore, you will need to do a lot of sanding too.

Hand files

Flat file

Half round file

Filing

I used two types of hand files for the base, the half round and flat file. As you can see the flat file is used for surfaces that isn't hard to shape and is for flatter surfaces (except curves that go outwards), while the half round file are more suitable for curves that go inwards in a smaller space (e.g. the middle part of my design). As you can see in the gif the flat file is used more often as I don't have much inwards curved except the middle part which I did not get to before the time-lapse ended.

Quick filing process

Sanding

The first photo on the far left is my foam model after using the hand files. On the left of this text box is my foam model after using the a P800 sandpaper (the higher the smoother the sandpaper, the lower the rougher).

Sides

By sanding the corners/edge of your design will make it look cleaner and smoother as you can see above.

Sanding

After using the P800 I used the P1000 to sand once more on the base to make it even smoother. As you can see in the photo on the right, you can barely see the scratch marks from the first photo now (though its still visible).

Neck

Assembling them

I got two long foam blocks and cut them into the following shapes in the photo on the left. The top block is the shape of a trapezium and is the longest, the middle is the shape of a parallelogram and it shorter than the top one, and the last block is the smallest rectangle. I tried to put them together using the thick wood sticks though it was too big and did not work. Then I tried using toothpicks (the larger sticks didn't have sharp ends with made it harder to stab it into the foam blocks, but because the toothpicks had sharp ends I was able to stab it in and put them together) and double sided tape, which did work. I stuck the double sided tape onto the top of the smallest and middle blocks, the same goes for the toothpicks.

Though they still fall off most the times...

I stuck the double sided tape and then stabbed the toothpick into the foam block after (through the tape). Aligned the blocks and pressed the other block onto another.

It looks alright though it's just a bit heavy to one side and keeps falling back-wards.

I felt like the front was too long so I cut a bit off with the hot wire then sanded it to make it smoother. I think I made the back of the middle foam block too small after sanding the end so I had to make it look like the bottom foam block is curving in.

Top

I couldn't find a block that matches the height I wanted it to be so I had to find random foam blocks of different sizes. I found three and stacked it on top of each other using double sided tape like what I did with the base. Using the same process as the previous parts, cut out your wanted shape with the hot wire and then if you want you can also sand it using the Band Facer (only flat surfaces though) instead of using the hand files all the time.

I used the hand file to chamfer the sides, then used wet and dry sand papers to make the model even smoother including the chamfered parts (so its between a fillet and a chamfer).

(← Band Facer)

Assembling Everything Together (+ Making The Lamp)

Mark out the size of your lamp's neck base with a pencil and use the hot wire to cut out the inside. ( you actually need to use a machine specially for cutting wood but my model was too large so I had to use the hot wire and ) Then sand the foam so that it touches the line using the flat hand file. Though I was not careful and did not check under my base (another pencil mark) to see whether it's tilted to one side like: \\

I figured out that the neck was too short so I added another block of foam I found and cut out. But then it was too small and won't stay in the slot (and it was also on in the center, when I looked from behind the model the neck was not lined in a straight vertical line) so I had to find a new foam block and find a way to fix the mistake.

I got a block of foam with a width that is bigger than the slot, traced the height of my old foam block that was the base of neck sanded, used the hot wire to cut around it and sanded it to fit the slot. I also sanded the top to tilt to the front a bit because I just thinks it looks better like that.

I used a new toothpick to put the two together. And since the sides are already perfect to the slot and is also quite smooth, I decided not to sand the sides any further with the sand paper. I did sand the corners though as the base is a bit bigger in length than the actual base of the neck.

I marked out how far the neck needed to be in the top with a pencil and got help from Mr Douglas. He used the Band saw to separate the top and the bottom two piece (together) from each other and cut out following the pencil marks of how deep the neck should be on the bottom piece, as you can see in the photo. Then, if you want to, use the flat file to smooth the cut a bit, though it's not necessary.

Stick the pieces back together using double sided tape.

To make the actual lamp part, grab a foam block and trace out a circle. Use the hot wire to cut the shape, then the hand files and sand paper (or the band facer) to make it smoother. I had to make two because I accidentally ruined it with the band facer ←.

For this step you'll need a black marker to trace out the parts that are resin in your design.

Final touches

Materials I used for this last step are toothpicks to put parts of the Styrofoam together, Styrofoam, a cutter (designed specially for cutting circles actually), a cutting mat, and (optional) a pencil/compass.

Use your compass or pencil to draw out your circle on the Styrofoam. Be sure to check if the ring will fit the neck of your model. Use the circular cutter to cut the inside out first then the outer part after, it's easier than the other way round (outer, inner). Next step is to cut a line in a part of the ring, slide the ring into the neck and using the toothpick, poke it through the ring and the foam model as shown in the finalized designs photos. Do the same for the Lamp (actual lamp part).

Final/Finished Design

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